msem-instigator

Search your library for a basic land card and put it onto the battlefield, then shuffle.
Orchestrate {1}{G} (You may exile this card from your hand anytime you could cast a sorcery for its orchestrate cost. When you next resolve a spell, you may cast this from exile without paying its mana cost.)

Enchant creature
Enchanted creature has haste and first strike.

Whenever a creature you control becomes the target of a spell, that creature gets +3/+3 until end of turn.

Surging Lightning deals 2 damage to target creature or planeswalker. If you've cast another spell this turn, it deals 4 damage instead.

Submerge up to two target attacking nontoken creatures an opponent controls. (To submerge a card, exile it, then put it on the battlefield face down under its owner's control as a 2/2 creature.)

You may have Surging Wurm assign its combat damage as though it weren't blocked.
Surging Wurm gets +2/+2 as long as seven or more cards are in your graveyard.

Target player draws X cards.

Target creature gains double strike and trample until end of turn. (Then exile this card. You may cast the creature later from exile.)

Until end of turn, target creature gets +1/+1 and gains lifelink.

Flash
When Surreal Bakhtak enters, choose one —
• Destroy target tapped creature.
• Tap up to three target creatures.

Flying, prowess
Whenever Surveyor of Skies attacks, you may return a permanent you control to its owner's hand.

When Surveyor's Rifle enters, rediscover a land card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a land card. Otherwise, put it back or into your graveyard.)
Equipped creature gets +2/+1.
Equip {3}

Wanderlust — When you cast this spell, you may copy it if you control four or more differently named lands. You may choose new targets for the copy.
Untap target creature you control. It gets +1/+1 and gains hexproof and indestructible until end of turn.

Regenerate target creature. (The next time this would be destroyed this turn, it isn't. Instead tap it.)

Return up to one target creature card and up to one target land card from your graveyard to your hand.

Spells you cast have trial 2. (As you cast them, an opponent of your choice may pay 2 life. If they don't, they fail the trial.)
Whenever an opponent fails a trial of a creature spell, that creature enters with an additional +1/+1 counter on it.
Whenever an opponent fails a trial of a noncreature spell, create a tapped Treasure token.

Prowess
When Surviving Scavengers enters, you may draw a card, then discard a card.

When Suspect Concoctions enters, put a +1/+1 counter on target creature.
{4}, Sacrifice Suspect Concoctions: Put two +1/+1 counters on target creature. (A suspected creature has menace and can't block.)

Haste
{T}, Discard a card: Flip a coin. If you win the flip, draw two cards. Otherwise, you may pay {R}. If you do, repeat this process.

Enchant land
Enchanted land has “{W}, {T}: You gain 2 life.”

As an additional cost to cast this spell, discard a card.
Return up to one target instant card and up to one target sorcery card from your graveyard to your hand. Exile Sustaining Meditation.

Deception {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Pay 1 life, Choose a creature card name you haven't chosen for Suzume Oshiruko this turn: Return another creature you control with the chosen name to its owner's hand.

Each other Rogue creature you control enters with an additional +1/+1 counter on it.
Remove a +1/+1 counter from a creature you control: That creature can't be blocked this turn.

Swallowed by the Earth deals 4 damage to target creature. Destroy all Equipment attached to that creature.

Primal {1}{G}{G} (During your turn, you may cast this spell for {1}{G}{G} instead of playing a land.)
When Swampedge Sentinel dies, return another creature card from your graveyard to your hand.